Helically wound plastic tubing with variable profile thickness and methods of making the same

ABSTRACT

Plastic tubing including a thermoplastic ribbon helically wrapped and heat bonded to itself to form a tubing wall and a thermoplastic reinforcement located helically around and along the tubing wall. At least a thickness of the tubing wall or a size of the thermoplastic reinforcement is varied along the tubing wall.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/971,435, filed on Mar. 27, 2014, which is hereby incorporated byreference in its entirety.

BACKGROUND

Various types of plastic tubing can include a relatively thin wall witha helical reinforcement. Such corrugated tubing can provide crushresistance while leaving the tubing flexible enough to allow forshort-radius bends without collapsing or kinking the tubing. Theversatility of this kind of tubing is evidenced by its use inconstruction, ventilation, manufacturing processes, auto washes,hospitals, medical devices, and other areas.

For certain uses of the above-described tubing, such as for medicaluses, it is also desired to provide interior and exterior surfacesmostly free of crevices to eliminate or reduce contaminates that mayreside in such crevices. In the case of inhalation therapies such asthose using CPAP (Continuous Positive Airway Pressure) and otherbreathing assistance methods, a smooth inner bore for the tubing is alsodesired to reduce flow resistance when airflow is conducted through thetubing.

To obtain relatively crevice-free interior and exterior surfaces, theabove-described tubing can be manufactured by extruding a plastic stripor ribbon and helically wrapping the ribbon upon itself while molten toform a tubing wall. In such a manufacturing process, a winding orwrapping head with multiple cantilevered and rotationally drivenmandrels or winding rolls can be spaced about a longitudinal axis forwinding and rotationally advancing helically wound tubing. In someexamples, at least one wire and a thermoplastic reinforcement can beplaced on the tubing wall while the tubing wall is formed. In suchexamples, the thermoplastic reinforcement heat bonds to the tubing wall.The tubing is then cooled to solidify before being cut intopredetermined lengths.

SUMMARY

Although the helically reinforced plastic tubing described above canprovide crush resistance while leaving the tubing wall flexible enoughto allow for short-radius bends without collapsing or kinking, portionsof such tubing can become easily damaged in the field. In one example,damage may occur to the ends of the tubing due to connections of thetubing to a particular machine such as a CPAP machine. Such damage tothe tubing ends may occur, for example, after repeated connection anddisconnection of the tubing in the field or from the additional stresson the tubing ends when the tubing is moved while connected. The tubingends may deform over time due to such mechanical stress or from thermalstress, and in some cases, the connection of the tubing may becomecompromised.

Although using heavier materials or thickening the tubing wall mayprovide a more durable tubing, this generally results in a heaviertubing with an increased cost. Heavier tubing can make the tubing morecumbersome to use, such as when the tubing is a vacuum hose that isphysically moved by an operator or where a heavier medical device tubingcan result in decreased patient comfort and mobility.

In view of the foregoing, the plastic tubing of the present disclosureincludes a tubing wall and a helical thermoplastic reinforcement locatedaround and along the tubing wall where at least a thickness of thetubing wall or a size of the reinforcement is varied along the tubingwall. By varying the thickness of the tubing wall and/or the size of thereinforcement, it is ordinarily possible to increase the durability ofthe tubing at particular locations along the tubing without increasingthe weight and cost of the tubing over the entire length of tubing.

For example, by having the ends of the tubing with a thicker wall and/ora larger helical reinforcement, the durability of the tubing isordinarily improved where the tubing is connected. In addition, adifferent size for the tubing wall and/or the helical reinforcement atan end of the tubing can allow for a tighter fit to a connection or canallow for connections having a different diameter than other portions ofthe tubing. For example, one end of the tubing may have a first outerdiameter while the other end and/or a middle portion of the tubing mayhave a different outer diameter.

Furthermore, increasing the size of the tubing wall and/or the helicalthermoplastic reinforcement at the end portions can improve cutting ofthe tubing during manufacturing since the increased size can oftenprovide a cleaner cut than a thinner material which may be more likelyto deform or rotate during cutting.

In other implementations, a heavier or thicker tubing may only be neededat certain points between the ends of the tubing or in addition to theends of the tubing. For example, tubing for a particular machine mayonly need increased durability at its ends and at a midpoint where thetubing is mounted in the machine.

In one embodiment of the present disclosure, a plastic tubing includes athermoplastic ribbon helically wrapped and heat bonded to itself to forma tubing wall. The tubing wall along its length includes a first endportion, a second end portion, and a middle portion between the firstend portion and the second end portion. The tubing wall is thicker atthe first end portion and at the second end portion than throughout themiddle portion of the tubing wall, and a helical thermoplasticreinforcement is located around and along the tubing wall.

According to other embodiments, the helical thermoplastic reinforcementis larger at the first and second end portions than throughout themiddle portion instead of or in addition to the tubing wall beingthicker at the first and second end portions.

In another embodiment, a first cross section of the thermoplastic ribbonacross a width of the thermoplastic ribbon has a greater area than asecond cross section of the thermoplastic ribbon, with the second crosssection located away from the first cross section along a length of thehelically wrapped thermoplastic ribbon.

According to another embodiment, a first cross section of the helicalthermoplastic reinforcement across a width of the reinforcement has agreater area than a second cross section of the helical thermoplasticreinforcement, with the second cross section located away from the firstcross section along a length of the reinforcement.

According to another embodiment, a method of making plastic tubingincludes forming a ribbon of molten thermoplastic and helically wrappingthe ribbon so that a portion of the ribbon overlaps upon itself and heatbonds to form a tubing wall. A thickness of the ribbon of moltenthermoplastic is varied to vary a thickness of the tubing wall.

According to yet another embodiment, a thermoplastic reinforcement isformed and helically disposed around and along the tubing wall to heatbond with the tubing wall with a size of the thermoplastic reinforcementbeing varied along the tubing wall. In yet another embodiment, both thethickness of the ribbon of molten thermoplastic and the size of thethermoplastic reinforcement are varied.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the embodiments of the present disclosurewill become more apparent from the detailed description set forth belowwhen taken in conjunction with the drawings. The drawings and theassociated descriptions are provided to illustrate embodiments of thedisclosure and not to limit the scope of what is claimed.

FIG. 1A is a side view of plastic tubing according to an embodiment.

FIG. 1B depicts a cross section of a tubing wall of the plastic tubingof FIG. 1A according to an embodiment.

FIG. 1C depicts another cross section of the tubing wall of the plastictubing of FIG. 1A according to an embodiment.

FIG. 2A depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including a thickened end portion of a tubing wallwith a larger helical thermoplastic reinforcement according to anembodiment.

FIG. 2B depicts a lengthwise cross sectional view of a plastic tubingduring manufacture with a flattened helical thermoplastic reinforcementalong an end portion of a tubing wall according to an embodiment.

FIG. 2C depicts a lengthwise cross sectional view of a plastic tubingduring manufacture with a cuff on an end portion of a tubing wallaccording to an embodiment.

FIG. 2D depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including a wire disposed around and along a tubingwall according to an embodiment.

FIG. 2E depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including wires within a helical thermoplasticreinforcement according to an embodiment.

FIG. 2F depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including a grooved plateau according to anembodiment.

FIG. 3 depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including a thickened tubing wall according to anembodiment.

FIG. 4 depicts a lengthwise cross sectional view of a plastic tubingduring manufacture including a helical thermoplastic reinforcement thathas been increased in size according to an embodiment.

FIG. 5 is a top view of a layout for manufacturing plastic tubingaccording to an embodiment.

FIG. 6 is a flowchart for a plastic tubing manufacturing processaccording to an embodiment.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth to provide a full understanding of the present disclosure. It willbe apparent, however, to one of ordinary skill in the art that thevarious embodiments disclosed may be practiced without some of thesespecific details. In other instances, well-known structures andtechniques have not been shown in detail to avoid unnecessarilyobscuring the various embodiments.

FIG. 1A is a side view of plastic tubing according to an embodimentwhere the tubing wall is thicker and the thermoplastic reinforcement islarger at the end portions of the tubing than throughout the middleportion of the tubing. As shown in FIG. 1A, tubing 10 includes first endportion 12, second end portion 14, and middle portion 16, which islocated between first end portion 12 and second end portion 14. Tubing10 includes thermoplastic ribbon 18 which has been helically wrapped andheat bonded to itself to form tubing wall 22.

In addition, tubing 10 includes helical thermoplastic reinforcement 20,which is located around and along tubing wall 22. In the embodiment ofFIG. 1A, helical thermoplastic reinforcement 20 is a bead of extrudedthermoplastic that has been wrapped around tubing wall 22 and heatbonded with tubing wall 22. As discussed in more detail below withreference to FIGS. 5 and 6, helical reinforcement 20 can be separatelyextruded from the extrusion of thermoplastic ribbon 18. In otherembodiments, helical reinforcement 20 can include a rib or protrusionfrom ribbon 18 such that helical reinforcement 20 is extruded withribbon 18. Examples of thermoplastics used for either ribbon 18 orreinforcement 20 can include polyethylene (PE), polypropylene (PP), orany other thermoplastic.

End portions 12 and 14 are not limited to a particular length orproportion of tubing 10. In this regard, end portions 12 and 14 can beseveral inches in some implementations or can be less than half an inchin other implementations. The length of end portions 12 and 14 can alsodiffer from each other. Similarly, middle portion 16 is not limited to aparticular length or proportion of tubing 10.

In FIG. 1A, cross section lines 1B and 1C are provided to show locationsfor cross sectional views of tubing wall 22 in FIGS. 1B and 1C,respectively. As shown in FIGS. 1B and 1C, tubing wall 22 is thicker forend portions 12 and 14 than throughout middle portion 16. A thickness orouter circumference of tubing wall 22 is shown to be the same at endportions 12 and 14, however, in practice, the thickness of tubing wall22 may vary slightly such that the thickness of tubing wall 22 will beapproximately the same (e.g., within 5% of each other). The thickness oftubing wall 22 may also generally increase in middle portion 16 duringthe transition from middle portion 16 to either of end portions 12 and14. However, in the example of FIGS. 1A to 1C, the thickness of tubingwall 22 is generally 15% thicker on average for end portions 12 and 14than for middle portion 16. This can ordinarily provide a more durabletubing wall at end portions 12 and 14 while allowing for a thinner, moreflexible, and lighter tubing wall throughout middle portion 16. Otherembodiments can include different changes in thickness of tubing wall22.

Helical reinforcement 20 is also larger for end portions 12 and 14 thanfor middle portion 16. In one implementation, reinforcement 20 is onaverage 20% larger for end portions 12 and 14 than for middle portion16. As with tubing wall 22, the average increase in size ofreinforcement 20 may differ in other embodiments.

Without magnification, tubing 10 may appear in some implementations asthough tubing wall 22 and reinforcement 20 have a uniform size acrossend portions 12 and middle portion 16. This appearance can be due to arelatively small dimensional scale for tubing wall 22 and reinforcement20. In some implementations, the difference in thickness, height, orwidth may only be noticeable by measurement with calipers or other finemeasurement tools. For example, in an implementation where the thicknessof tubing wall 22 increases on average by approximately 14% in endportions 12 and 14 compared to middle portion 16, the measureddifference in the average thickness of tubing wall 22 may be 0.03 mm.Similarly, the average height and width of the profile of reinforcement20 may increase by 9% and 13%, respectively, but with an averageincrease in height of 0.15 mm and an average increase in width of 0.35mm. Accordingly, the variation in tubing wall thickness or reinforcementsize may be more or less noticeable to the naked eye depending on thedimensional scale of tubing wall 22 and reinforcement 20. In thisregard, the variation in tubing wall thickness or reinforcement sizewill generally be more noticeable where dimensions of tubing wall 22 orreinforcement 20 are larger than the example dimensions provided above.

Although end portions 12 and 14 include a thickened tubing wall 22 and alarger reinforcement 20 than middle portion 16, other embodiments caninclude one or both of these features at only one of end portion 12 orend portion 14, or in middle portion 16 instead of at the end portions.

FIG. 2A depicts a lengthwise cross sectional view of a plastic tubingwhich includes an end portion with a thickened tubing wall 22 and alarger helical reinforcement 20 according to an embodiment. As shown inFIG. 2A, ribbon 18 is helically wrapped and heat bonded to itself toform tubing wall 22. Cross sections of ribbon 18 are shown in FIG. 2Aacross the width of successive wraps of ribbon 18. A portion of eachwrap of ribbon 18 overlaps upon a previous wrap of ribbon 18 at overlaps24, which are shown somewhat exaggerated for ease of explanation. Inmost implementations, overlaps 24 are virtually coplanar heat bonds.

The last two overlaps on the left side of FIG. 2A are shown with adashed line rather than a solid line to illustrate the fusing of thewraps of ribbon 18 into an integral whole. The overlaps at what wereonce individual parts is indicated in FIGS. 2A to 4 with dashed lines.

In addition, helical reinforcement 20 is disposed onto overlaps 24 andheat bonds to form an integral part of tubing 10. In other embodiments,helical reinforcement 20 can be located away from overlaps 24 or on topof another portion of ribbon 18 or on an intermediate layer on tubingwall 22. In yet other embodiments, reinforcement 20 can be a part ofribbon 18 such as a rib or a protrusion from ribbon 18.

The cross sectional view of FIG. 2A provides a view of tubing 10 as itis being formed and before it is cut along cut line 28. Ribbon 18 isinitially overlapped on the right side of FIG. 2A forming overlap 24.The amount of overlap of ribbon 18 can vary in different embodiments sothat the width of overlap 24 varies from that shown in FIG. 2A.Reinforcement 20 is then disposed on overlap 24 as ribbon 18 andreinforcement 20 are advanced in the direction of the arrow.

As shown in FIG. 2A, the cross sections of ribbon 18 in end portion 12have a greater area or profile across a width of ribbon 18 than thecross sections of ribbon 18 in middle portion 16. In addition, the crosssections of reinforcement 20 are larger in end portion 12 than in middleportion 16. The durability of the tubing in end portion 12 is generallyimproved by increasing the size of ribbon 18 and reinforcement 20 whilekeeping middle portion 16 relatively flexible and lightweight. In otherembodiments, a different number of wraps of ribbon 18 and/orreinforcement 20 are possible so as to have a different number of crosssections for ribbon 18 and/or reinforcement 20 than those shown in FIG.2A.

In the example of FIG. 2A, tubing wall 22 is cut within thickenedportion 26, where tubing wall 22 has been thickened and the size ofreinforcement 20 has been increased. By cutting tubing wall 22 withinthickened portion 26, an end portion for another tubing can be formed tothe left of end portion 12. In addition, cutting the tubing within athickened portion of tubing wall 22 and/or a larger portion of helicalthermoplastic reinforcement ordinarily reduces the likelihood ofdeformation to tubing wall 22 or reinforcement 20 from cutting at cutline 28.

FIG. 2B depicts a lengthwise cross sectional view of tubing with aflattened helical reinforcement along end portion 12 of tubing wall 22according to an embodiment. As with FIG. 2A, the cross sections ofreinforcement 20 and ribbon 18 in end portion 12 have more area than thecross sections of reinforcement 20 and ribbon 18 in middle portion 16.However, reinforcement 20 has been flattened in thickened portion 26,which includes end portion 12. Although reinforcement 20 may be tallerin middle portion 16, reinforcement 20 is larger with a greater crosssectional area in end portion 12 than in middle portion 16.

A roller can be used to flatten reinforcement 20 soon after ribbon 18has been overlapped to form tubing wall 22 before it completely hardens.Even in a flattened state, increasing the size of reinforcement 20within end portion 12 ordinarily provides better durability of thetubing. In some implementations, reinforcement 20 is flattened to betteraccommodate a cuff encircling at least part of end portion 12, as shownin FIG. 2C with cuff 30.

The amount of end portion 12 that is covered by cuff 30 can differ basedon different design criteria for the tubing, such as for differentamounts of strain relief. For example, some implementations may includeseveral inches of end portion 12 that is not covered by cuff 30 whileother implementations may include very little or no portion of endportion 12 that is not covered by cuff 30.

FIG. 2D depicts a lengthwise cross sectional view of plastic tubingincluding wire 32 disposed around and along tubing wall 22 according toan embodiment. As with the tubing of FIGS. 2A to 2C, the tubing of FIG.2D includes ribbon 18 and helical reinforcement 20, which are bothlarger in end portion 12 than in middle portion 16. However, the exampleof FIG. 2D includes wire 32 helically disposed adjacent overlaps 24.Wire 32 can be wrapped around tubing wall 22 after ribbon 18 has beenhelically wrapped to form overlap 24. In some implementations, wire 32can be used to heat a fluid such as air conducted inside tubing wall 22.In other implementations, wire 32 can be used to transmit signals alongtubing 10.

For resistance heating purposes, wire 32 can be formed of copper,although resistive metal such as nickel-chromium may also be used. Fortransmitting signals, wire 32 can include an electrically or opticallyconductive material such as metals, conductive polymers, or opticalfiber. Wire 32 may also include a twisted pair of electrical conductors.

In the embodiment of FIG. 2D, reinforcement 20 is disposed helically ontop of wire 32 to insulate wire 32 as well as to provide crush andkinking resistance for tubing 10. In other embodiments, the tubing caninclude multiple wires positioned adjacent, on or away from overlaps 24.

FIG. 2E depicts a lengthwise cross sectional view of an embodiment of aplastic tubing including multiple wires 32 within helical reinforcement20. In such an embodiment, wires 32 can be embedded within reinforcement20 before reinforcement 20 is helically disposed on tubing wall 22.Wires 32 in FIG. 2E can be used for heating and/or electric signaltransmission along the tubing.

As with the tubing of FIGS. 2A to 2D, both the cross sections of ribbon18 and reinforcement 20 are larger in end portion 12 than in middleportion 16.

FIG. 2F depicts a lengthwise cross sectional view of an embodiment of aplastic tubing including grooved plateau 34 on one end of ribbon 18.Plateau 34 is elevated along an edge of ribbon 18 so as to helicallywrap around and along tubing wall 22. As shown in FIG. 2F, three wires32 are placed in grooves of plateau 34 before reinforcement 20 is placedupon plateau 34 to cover wires 32. The location of plateau 34 is notlimited to a particular location. In addition, the number or arrangementof wires 32 may differ in other embodiments.

As with the tubing of FIGS. 2A to 2E, both the cross sections of ribbon18 and reinforcement 20 are larger in end portion 12 than in middleportion 16. Although the thickness of ribbon 18 may vary across a widthof ribbon 18 due to plateau 34, the area of each cross section of ribbon18 across its width (including plateau 34) is greater in end portion 12than the areas of each cross section of ribbon 18 in middle portion 16.

FIG. 3 depicts a lengthwise cross sectional view of a plastic tubingaccording to an embodiment where tubing wall 22 is thicker in endportion 12, but reinforcement 20 remains substantially the same size asin middle portion 16. As shown in FIG. 3, each cross section of ribbon18 in end portion 12 has a greater area across a width of ribbon 18 thanthe cross sections of ribbon 18 in middle portion 16.

FIG. 4 depicts a lengthwise cross sectional view of an embodiment wherereinforcement 20 has been increased in size in end portion 12, butribbon 18 remains substantially the same size in both middle portion 16and end portion 12. As shown in FIG. 4, each cross section ofreinforcement 20 in end portion 12 has a greater area across the widthof reinforcement 20 than the cross sections of reinforcement 20 inmiddle portion 16. Such an increase in the size of reinforcement 20 canallow for increased durability of the tubing while not significantlyinterfering with thermal conduction from wires 32 to fluid conductedwithin the tubing. The example of FIG. 4 may also allow for flexibilityof tubing wall 22 in end portion 12 by not also thickening tubing wall22.

FIG. 5 is a top view of a layout for manufacturing plastic tubing 10according to an embodiment. As shown in FIG. 5, mandrel motor 114 isconfigured to rotate mandrels 102, which are canted and spaced aboutlongitudinal axis 104 for winding and rotationally advancing tubing 10.In one implementation, the mandrels can rotate together in a clockwisedirection.

First extruder 106 is configured to extrude ribbon 18 including leadingedge 36 and trailing edge 38. Second extruder 108 is configured toextrude thermoplastic reinforcement 20. Although first extruder 106 andsecond extruder 108 are shown as physically separate extruding machinesfor ease of explanation in FIG. 5, it should be understood that bothribbon 18 and reinforcement 20 may be extruded from a single extrusionmachine with a co-located die.

Ribbon 18 is discharged in a molten state from first extruder 106 andhelically wrapped about mandrels 102 so that it encircles mandrels 102and wraps upon itself at overlap 24 to form successive wraps of ribbon18 in tubing wall 22. As tubing wall 22 cools and solidifies, it isadvanced toward the left in the direction of the arrow

Wire feeding mechanism 110 employs payout mechanism 112 for feeding andembedding wire 32 along leading edge 36 of each overlap 24 just prior toapplication of reinforcement 20 to tubing 10 as shown. Wire 32 is fed ata particular draw angle using trough 118 as a guide.

The canting of mandrels 102 causes tubing 10 to move continuously in adownstream direction indicated by the arrow. In the example embodimentof FIG. 5, cooling conduit 116 sprays water directed radially outwardlyagainst the inner surface of tubing 10, and also in the downstreamdirection which assists in removing tubing 10 after cutting.

Cutting mechanism 120 is configured to cut tubing 10 in determinedlengths. In the embodiment of FIG. 5, cutting mechanism 120 isconfigured to periodically cut tubing 10 at a predetermined time periodcorresponding to a particular length for tubing 10. In addition, thecutting of tubing 10 is coordinated with mandrel motor 114 so as tooccur at cut line 28 to form end portions 12 and 13, which include athickened tubing wall 22 and/or a larger reinforcement 20. In thisregard, the cutting of tubing 10 can also be coordinated with a speed ofextruder 106, extruder 108, and/or mandrel motor 114. As described inmore detail below with reference to FIG. 6, increasing the speeds ofextrusion of ribbon 18 and reinforcement 20 with respect to the speed ofmandrel motor 114 can result in a thickening of tubing wall 22 and alarger reinforcement 20. In addition, the slowing of mandrel motor 114with respect to the speeds of extruders 106 and 108 can result in athickening of tubing wall 22 and a larger reinforcement 20.

As shown in FIG. 5, the coordination of cutting mechanism 120 withextruder 106, extruder 108, and/or mandrel motor 114 can be accomplishedthrough programming at controller 122, which is electrically connectedto extruder 106, mandrel motor 114, and extruder 108. Controller 122 caninclude a processor for executing computer-readable instructions storedin a memory of controller 122. In addition, controller 122 can include auser interface such as a touchscreen to allow for configuration of theoperation of cutting mechanism 120, mandrel motor 114, and extruders 106and 108. In other embodiments, the configuration of operation for any ofcutting mechanism 120, mandrel motor 114, and extruders 106 and 108 canbe accomplished by separate controllers for each of these devices.

FIG. 6 is a flowchart for a plastic tubing manufacturing processaccording to an embodiment. The process of FIG. 6 begins with formingribbon 18 of molten thermoplastic in block 202. This can be accomplishedusing an extruder such as extruder 106 in FIG. 5. Ribbon 18 is thenhelically wrapped around rotating mandrels 102 in block 204 so that aportion of ribbon 18 overlaps upon itself and heat bonds to form tubingwall 22.

In block 206, wire 32 is helically disposed around and along tubing wall22 using wire feeding mechanism 110, payout mechanism 112, and trough118 to guide wire 32 onto leading edge 36 at a particular draw angle. Inother embodiments, multiple wires may be helically disposed around andalong tubing wall 22 or wire 32 may be located on a different portion oftubing wall than leading edge 36, such as into a groove along tubingwall 22. In yet other embodiments, block 206 may be omitted so that nowires are helically disposed on tubing wall 22.

In block 208, thermoplastic reinforcement 20 is formed by extruder 108.Reinforcement 20 can also be molten when formed as with ribbon 18 or mayhave already cooled so that it is no longer molten. Conversely, ribbon18 may have already been cooled and thermoplastic reinforcement 20 canbe molten. In other embodiments, reinforcement 20 and ribbon 18 can beformed together so that ribbon 18 and reinforcement 20 are formed by thesame extruder. In such an embodiment, reinforcement 20 can include a ribor other protrusion extending from ribbon 18.

In block 210, reinforcement 20 is helically disposed around and alongtubing wall 22 to heat bond with tubing wall 22. As shown in FIG. 5,reinforcement 20 is disposed so as to cover or encircle wire 32 atoverlap 24. In other embodiments, reinforcement 20 can be disposed atother locations around and along tubing wall 22 such as between overlaps24. In some embodiments, a roller may also flatten a portion ofreinforcement 20 soon after reinforcement 20 is located on tubing wall22 as shown in the tubing of FIGS. 2B and 2C.

In block 212, either the thickness of ribbon 18 or the size ofreinforcement 20 is varied, or both the thickness of ribbon 18 and thesize of reinforcement 20 are varied. In one implementation, varying thethickness of ribbon 18 includes varying a speed at which extruder 106extrudes ribbon 18 while mandrel motor 114 is kept at the same speed.When extruder 106 is sped up, ribbon 18 becomes thicker since tubingwall 22 continues to advance at the same rate. Extruder 106 can beconfigured to speed up for a certain period of time for thickened endportions of tubing wall 22, and then return to the slower speed for athinner middle portion 16 of tubing wall 22. Extruder 106 can alternatebetween the two different speeds. In one example, a motor of extruder106 may speed up to a high RPM for two seconds, slow down to a low RPMfor six seconds, and then speed back up to the high RPM for two secondsThis cycle can be repeated so as to form successive end portions andmiddle portions.

Extruder 108 can also be sped up in block 212 while mandrel motor 114remains at the same speed to form a larger reinforcement 20. Similar toextruder 106, extruder 108 can be configured to speed up for certainperiod of time for a larger reinforcement 20 along end portions oftubing wall 22, and then return to the slower speed for a smallerreinforcement 20 along middle portion 16 of tubing wall 22.

In other embodiments, a speed of mandrel motor 114 can be varied withrespect to the speed of either or both extruders 106 and 108 to varyeither or both the thickness of tubing wall 22 and the size ofreinforcement 20. If mandrel motor 114 is slowed down while extruders106 and 108 remain at the same speeds, tubing wall 22 becomes thickerand reinforcement 20 increases in size. In another exampleimplementation, if mandrel motor 114 and extruder 106 are slowed downwhile extruder 108 remains at the same speed, reinforcement 20 increasesin size while tubing wall 22 remains substantially the same size. Toincrease a thickness of tubing wall 22, mandrel motor 114 and extruder108 can be slowed down while extruder 106 remains at the same speed.

In block 214, tubing wall 22 and reinforcement 20 are cooled either byair, water or a combination of both. In the example of FIG. 5, tubingwall 22 and reinforcement 20 can be cooled by both a water bath beforereaching cutting mechanism 120 and by cooling from cooling conduit 116.As tubing wall 22 and reinforcement 20 cool, they bond together to formintegral components of tubing 10.

In block 216, tubing wall 22 is cut by cutting mechanism 120 within aportion of tubing wall 22 where it has been thickened and/or the size ofreinforcement 20 has been increased. Such a portion of tubing wall cancorrespond to thickened portion 26 so as to form two end portions with athickened tubing wall and/or a larger reinforcement 20. Cuttingmechanism may periodically cut tubing wall 22 so as to repeatedlyproduce tubing of a determined length as it is advanced along mandrels102.

In block 218, one or more cuffs such as cuff 30 are affixed to the endsof tubing 10. The cuffs may be affixed via over-molding, or by usingother methods known in the art. In other embodiments, block 218 may beomitted such that no cuffs are affixed to the ends of the tubing.

The foregoing description of the disclosed example embodiments isprovided to enable any person of ordinary skill in the art to make oruse the embodiments in the present disclosure. Various modifications tothese examples will be readily apparent to those of ordinary skill inthe art, and the principles disclosed herein may be applied to otherexamples without departing from the spirit or scope of the presentdisclosure. The described embodiments are to be considered in allrespects only as illustrative and not restrictive and the scope of thedisclosure is, therefore, indicated by the following claims rather thanby the foregoing description. All changes which come within the meaningand range of equivalency of the claims are to be embraced within theirscope.

What is claimed is:
 1. A plastic tubing, comprising: a thermoplasticribbon helically wrapped and heat bonded to itself to form a tubingwall, wherein a first cross section of the thermoplastic ribbon across awidth of the thermoplastic ribbon at a first end portion of the tubingwall has a greater area than a second cross section of the thermoplasticribbon across the width of the thermoplastic ribbon, the second crosssection of the thermoplastic ribbon located away from the first crosssection of the thermoplastic ribbon along a length of the helicallywrapped thermoplastic ribbon, and wherein a third cross section of thethermoplastic ribbon across the width of the thermoplastic ribbon at asecond end portion of the tubing wall has approximately the same area asthe first cross section of the thermoplastic ribbon, and wherein thesecond cross section of the thermoplastic ribbon is located between thethird cross section of the thermoplastic ribbon and the first crosssection of the thermoplastic ribbon along a length of the helicallywrapped thermoplastic ribbon; and a helical thermoplastic reinforcementlocated around and along the tubing wall.
 2. The plastic tubing of claim1, wherein a first cross section of the helical thermoplasticreinforcement across a width of the helical thermoplastic reinforcementhas a greater area than a second cross section of the helicalthermoplastic reinforcement across the width of the helicalthermoplastic reinforcement, the second cross section of the helicalthermoplastic reinforcement located away from the first cross section ofthe helical thermoplastic reinforcement along a length of the helicalthermoplastic reinforcement.
 3. The plastic tubing of claim 2, wherein athird cross section of the helical thermoplastic reinforcement acrossthe width of the helical thermoplastic reinforcement has approximatelythe same area as the first cross section of the helical thermoplasticreinforcement, and wherein the second cross section of the helicalthermoplastic reinforcement is located between the third cross sectionof the helical thermoplastic reinforcement and the first cross sectionof the helical thermoplastic reinforcement along a length of the helicalthermoplastic reinforcement.
 4. The plastic tubing of claim 1, whereinthe tubing wall along its length includes a middle portion between thefirst end portion and the second end portion, and wherein the tubingwall is thicker at the first end portion and at the second end portionthan throughout the middle portion.
 5. The plastic tubing of claim 1,wherein the tubing wall along its length includes a middle portionbetween the first end portion and the second end portion, and whereinthe helical thermoplastic reinforcement is larger at the first endportion and at the second end portion than throughout the middleportion.
 6. A plastic tubing, comprising: a thermoplastic ribbonhelically wrapped and heat bonded to itself to form a tubing wall; and ahelical thermoplastic reinforcement located around and along the tubingwall, wherein a first cross section of the helical thermoplasticreinforcement across a width of the helical thermoplastic reinforcementat a first end portion of the tubing wall has a greater area than asecond cross section of the helical thermoplastic reinforcement acrossthe width of the helical thermoplastic reinforcement, the second crosssection of the helical thermoplastic reinforcement located away from thefirst cross section of the helical thermoplastic reinforcement along alength of the helical thermoplastic reinforcement, wherein a third crosssection of the helical thermoplastic reinforcement across the width ofthe helical thermoplastic reinforcement at the second end portion of thetubing wall has approximately the same area as the first cross sectionof the helical thermoplastic reinforcement, and wherein the second crosssection of the helical thermoplastic reinforcement is located betweenthe third cross section of the helical thermoplastic reinforcement andthe first cross section of the helical thermoplastic reinforcement alongthe length of the helical thermoplastic reinforcement.
 7. The plastictubing of claim 6, wherein a first cross section of the thermoplasticribbon across a width of the thermoplastic ribbon has a greater areathan a second cross section of the thermoplastic ribbon across the widthof the thermoplastic ribbon, the second cross section of thethermoplastic ribbon located away from the first cross section of thehelical thermoplastic reinforcement along a length of the helicallywrapped thermoplastic ribbon, wherein a third cross section of thethermoplastic ribbon across the width of the thermoplastic ribbon hasapproximately the same area as the first cross section of thethermoplastic ribbon, and wherein the second cross section of thethermoplastic ribbon is located between the third cross section of thethermoplastic ribbon and the first cross section of the thermoplasticribbon along the length of the helically wrapped thermoplastic ribbon.8. The plastic tubing of claim 6, wherein the tubing wall along itslength includes a middle portion between the first end portion and thesecond end portion, and wherein the tubing wall is thicker at the firstend portion and at the second end portion than throughout the middleportion.
 9. The plastic tubing of claim 6, wherein the tubing wall alongits length includes a middle portion between the first end portion andthe second end portion, and wherein the helical thermoplasticreinforcement is larger at the first end portion and at the second endportion than throughout the middle portion.
 10. A plastic tubing,comprising: a thermoplastic ribbon helically wrapped and heat bonded toitself to form a tubing wall, the tubing wall along its length includinga first end portion, a second end portion, and a middle portion betweenthe first end portion and the second end portion, wherein a first crosssection of the thermoplastic ribbon across a width of the thermoplasticribbon at the first end portion has a greater area than a second crosssection of the thermoplastic ribbon at the middle portion, and wherein athird cross section of the thermoplastic ribbon across a width of thethermoplastic ribbon at the second end portion has a greater area thanthe second cross section; and a helical thermoplastic reinforcementlocated around and along the tubing wall.
 11. The plastic tubing ofclaim 10, wherein the helical thermoplastic reinforcement is larger atthe first end portion and at the second end portion of the tubing wallthan throughout the middle portion of the tubing wall.
 12. The plastictubing of claim 10, wherein the tubing wall is thicker at the first endportion and at the second end portion than throughout the middleportion.
 13. A plastic tubing, comprising: a thermoplastic ribbonhelically wrapped and heat bonded to itself to form a tubing wall, thetubing wall along its length including a first end portion, a second endportion, and a middle portion between the first end portion and thesecond end portion; and a helical thermoplastic reinforcement locatedaround and along the tubing wall, wherein a first cross section of thehelical thermoplastic reinforcement across a width of the helicalthermoplastic reinforcement at the first end portion has a greater areathan a second cross section of the helical thermoplastic reinforcementat the second end portion, and wherein a third cross section of thehelical thermoplastic reinforcement across a width of the helicalthermoplastic reinforcement at the second end portion has a greater areathan the second cross section of the helical thermoplasticreinforcement.
 14. The plastic tubing of claim 13, wherein the helicalthermoplastic reinforcement is larger at the first end portion and atthe second end portion of the tubing wall than throughout the middleportion of the tubing wall.